Process for activating provitamins



B. KRAMER ET AL.

PROCESS FOR ACTIVATING PROVITAMINS Filed March 19, 1936 VARIABLE 9-1VOLTAGE sou RCE CURRENT CYCLES PER SECONU INVENTCRS BENJAMIN KEAMEESAMUEL NATEZLSO/V ALEEWA'SOEKL m g .1 ATTORNEY Patented Mar. 29, 1938 gUNITED STATES PATENT OFFICE I PROCESS Fort ACTIVATING PiiovITAMINsBenjamin Kramer, Samuel Natelson, and'Albei-t E Sobel, Brooklyn, N. Y. I

- Application March 19, 1936, Serial No. 69,736

9Ciaims. (01104-31) This invention relates to antirachitic vitaminsantirachitic vitamin yield will be materially diand, more particularly,relates to novel apparatus 'minished. On the other hand, improperapplicafor and methods of converting provitamins into tion of too high apotential for that frequency antirachitic vitamins. etc. may result. ina. spark discharge .which will Heretofore, several methods have beenproposed destroy the provita'mins. Application of freand used toantirachitically. activate foods and quencies below or above thecritical range also sterols having no antirachitic potency. The mostreduces the efiiciency of antirachitic conversion of Y widely acceptedprocess for antirachitically' actithe provitamins. w vating substancescomprises exposure to a source We have found that the most economicalpro- 10 of ultra-violetJlight. Commercial production by duction ofsubstances containing antirachitic vita- 10 such a process requires anexpensive investment mins is to activate ergosterol or crude cholesterolin materials, particularly quartz. A quartz and subsequently introduce asmall percentage of mercury arc lamp is used to generate ultra-violetthe activated sterols to foods and medicines, for rays which aredirected upon the substance in a example yeast, olive oil, milk, codliver oil and the I solid state or, more generally, in a suitable liquidlike. The ergosterol or crude cholesterol is ap- 15 solution containedin quartz flasks or the like. p ied b twee t electrodes of e appa a usac- Production of ultra-violet light by sources other cording to ourpresent invention, preferably ina than a mercury arc lamp, such as theglow dissolid,loosely powdered state. Inanother form of charge, open arcdischarges or thecorona disour invention, the sterols or provitamin isdison charge are relatively inefficient. Exposure of prosolved in asuitablesolvent as, for example, ether 00 vitamins to open are or coronadischarges results and introduced between the discharge electrodes inthe destruction of the vitamin almost as rapidly in a fine spray; a i asit is formed.v The other proposed" methods for We have found that theprocess according to antirachitically activating :provitamins are of ourpresentinvention also has a sterilizing effect mere laboratory.significance on account of the uponthefoodsor Subs ances subjected to itin that i very low efiicienoies of conversion together with bacteria,PrOtO Oa' other micro-Organisms are the expensive apparatus and theskilled manipudestroyed. Foods which possess antirachitic lationrequired. These methods include: cxp pe s in a greater 0 less r such asmilk, posure of the material .to Xrays; bombardment olive oil, yeast,cod liver oil and the like, may be of the material by electrons in acathode ray directly activated by the brushdischarge ap- 30 tubesubjection of the material to a high frep r t s of our presentinvention.

quency alternating current greater than a Accordingly, an object of ourinvention is to thousand cycles. provide novel methods of convertingprovitamins We have discovered a simple, inexpensive and intoantiratchitic vitamins. 3;; very efficient method of'antiratchiticallyactivat- Another object of our invention is to convert 3 ing provitaminsy an electric dischargey a provitamins into antirachitic vitamins by abrush extended investigation of the action of the-difdischarge, ferenttypes of electrical discharges through gases further object of ourinvention is to provide uponprovitamins, We have" discovered that ysimple, inexpensive and efficient apparatus for 4o care y Controllingthe r ou p m a and methods of converting provitamins such as 0 criticalcondition exists whereby the conversion of sterols i t antirachitjcvitamins provitamins to antiratchitic vitaminsis extremely still afurthe Object of our invention is to fav ra le. The Critical electriflaldischarge, e vide novel apparatus for andmethods of sterilizerallyreferred to as the brush discharge, performs m f d Substances theefficient antiratchitic conversion. We have These and other objects ofOur'invention Wm 45 found that r a partlcular physlcal apparatus a beevident in the following description in connec most favorablevoltageexists, dependent upon the on with the drawin in which spacing ofthe electrodes between which the material is placed and thata mostsuitable frequency 3? 1 is Sc emanc dlagram usedtm the so of applicationof the alternating current exists of descnptlon of mdischarge phenomenathe order of 250-350 cycles. As will be explained t gases in more detailhereinafter, a voltage below the Figure 2 is a qualitative graphicalrepresentacritical for a particular frequency, area and spaction of thee l gaseous electric a ge ing of the plates and dielectric will producea glow phenomena.

r, discharge instead of a brush discharge and the Figure 3 is amodification of Figure'l.

Figure 4 is a partial perspective illustration of a preferred embodimentof our present invention.

Figure 5 is a qualitiative curve representing the efliciency ofconversion of provitamins to antirachitic vitamins withwrespect to thefrequency of the applied alternating current potential.

When a voltage is applied between two spaced conductors having a gaseousatmosphere between, a number of distinct types of electrical dischargesmay take place between the plates through the gas dependent upon thenature and magnitude of the potential applied to these plates. A varietyof phenomena accompanies gaseous electrical discharges includingluminous, thermal, magnetic, mechanical and chemical effects in varyingdegrees. In accordance with our present invention, the chemical actionof the electrical discharge is utilized and the conditions of operationare adjusted so as to produce the type of discharge having a maximumchemical action and a minimum of the other physical actions. This typeof electrical discharge is known as the brush discharge.

In order to clearly set forth the critical parameters for optimumantirachitic conversion of the materials, the following discussion as tothe several types of electrical discharge is presented.

Referring to Figure 1, two metallic plates l0 and II are spaced fromeach other by a flxed amount, for example, one centimeter. The space I!between electrodes lil and II contains a gaseous atmosphere for exampleordinary air at atmospheric pressure. A variable high potential orvoltage source I3 is connected to plates l0 and Ii by correspondingconductors I4 and it.

An ammeter 5 may be inserted in series with conductor ii for observationof the current flowing during an electrical discharge between plates inand ii.

Figure 2 is a graph representing the variation in with a fixed spacing.At low voltages, for example below one thousand volts, practically nocurrent will flow between the electrodes. As the voltage between theplates i0 and II is slowly increased, minute current will ilow betweenthem as represented by curve ii. The discharge I1 is characteristicallynon-luminous or invisible and is accompanied by negligible chemical orother physical efiects. At a certain region I! which is definite forgiven conditions of temperature, pressure and electrode spacing the glowdischarge begins which represents a discontinuity in the graph. Curve l9represents the voltage-current relation of the glow discharge. Thevoltage may be increased to a very high value and the glow dischargewill still be maintained and the current will correspondingly increase.The glow discharge is accompanied by a characteristic luminosity whichincludes ultra-violet light.

As the voltage is further increased, it will reach a peak value which ispractically the maximum voltage which the electrodes i0--Il can supportfor a particular gaseous atmosphere and spacing. The glow dischargedisappears at the 'region 20 and the characteristic brush dischargeoccurs. The brush discharge has sometimes also been called the silentdischarge or the dark discharge. These terms are misnomers since thebrush discharge is neither silent nor dark for it is attended by apeculiar sound and by some light.

By the term brush discharge as used hereinafter in the specification andclaims, we refer to the electrical discharge produced across a region bya voltage gradient which corresponds to substantially the maximumvoltage which can be supported between the electrodes bounding theregion, other conditions remaining the same. We further distinguish thebrush discharge as the electrical discharge occurring after the glowdischarge, on increasing the voltage, and corresponds to the regioncharacterized by the curve portion 20 of Figure 2. The brush dischargecorresponds in Figure 2 to the discharge produced in the vicinity of thepeak voltage ea. Other conditions which aifect the particular brushdischarge voltage for carrying out our process are the frequency of theapplied voltage, the spacing of the bounding electrodes, the characterof dielectric material used and the gaseous condition within thedischarge region.

The brush discharge is maintained by careful adjustment of the voltagefor a given structure. Increasing the electrical energy or currentsupply to the electrodes causes the production of the spark dischargerepresented by region 1|. Region 22 represents the electric flame whichresults from further increasing the current supply. Curve 23 representsthe negative voltage-current characteristic of the high tension arc andregion 24 represents the low tension are as is well known by thoseskilled in the art. It is to be understood that the graph plotted inFigure 2 is merely a qualitative representation of the several types ofelectrical discharge phenomena and that the actual voltage and currentdepend upon the type,

surface area and shape of the oppositely disposed electrodes, thespacing between said electrodes, the type of gas and its temperature andpressure as contained between the electrodes. The type of voltage whichproduces the electrical discharge characteristics represented in Figure2 may be an interrupted direct current or an alternating currentvoltage. The frequency of the interruptions or alternations of thevoltage source should be relatively low, for example, below a thousandcycles, otherwise diiferent electrical actions will occur. Asthefrequency of the voltage source is increased, the peak voltagesupported, corresponding to so of Figure 2, will be lowered. An increasein frequency will increase the current flow between the electrodesIll-II due to a capacitative or reactive current flow due to thefunction of the plates |I| ll as an electrical condenser.

The phenomena of the electrical discharge becomes more complicated thanthe relatively simple representation of Figure 2 when dielectricmaterial is interposed between the electrodes ill-4 I.

Referring to Figure 3, a glass plate 25 is placed adjacent to the innersurface of electrode ill and another glass plate 26 at the inner surfaceof plate ii. A variable high potential alternating current source 21 isapplied to the conductors i4--II. If the generator 21 is operated at twohundred cycles and the voltage applied to the electrodes Ill and II isincreased until the brush discharge corresponding to curve 20 in Figure2 occurs, it will be found that the brush discharge will occur when theelectrodes l0 and I l arecloser together than the corresponding casewhere no dielectric plates 25-26 are used. If the plates l0 and i l ofFigure 3 are separated a distance equal to that described in connectionwith Figure 1, namely one centimeter, then the maximum voltagecorresponding to an of Figure'2 will be greater at the brush discharge.The higher voltage is due to the presence of the dielectric material,namely the glass plates 2526 interposed beevident that a brush dischargemay be produced between two electrodes as long as ,a gaseous atmosphereexists between them, and that it is difficult to express the value ofthe voltage to be applied for all conditions. If the frequency ofgenerator 21 is increased, the maximum voltage which a given dischargestructure can support will be lessened.

The critical spacing of the electrodes maybe determined foraparticularvoltage and frequency supply as follows: The electrodes l0 and II, withs the dielectric materials 25 and 26 in place (Fig. 3)

if required, are connected to the supply and are gradually broughttogether until the easily recognizable spark discharge begins. Theelectrodes are then slowly moved apart until the spark discharge justdisappears. The brush discharge will then be evident to those. skilledin the art. 7

We have discovered that provitamins placed in the electrostatic fieldwithin a brush discharge are efficiently converted into antirachiticvitamins. We have also found that the antirachitic conversion isrelatively insignificant for electrical discharges occurring at thelower voltages, namely the non-luminous discharge represented by curveI! .in Figure 2 and the glow discharge represented by curve l9; and thatthe discharges occurring beyond the brush discharge,v namely the sparkdischarge and the electric are discharges represented by curves 2|, 22,23 and 24 of Figure 2 actually destroy the provitamins. It

is to be, understood thatthe brush discharge represents anelectrochemical conversion of theprovitamin to the antirachitic vitamin.This electrochemical action is analogous to the production ofozone-which has also been found to be most efficient in the brushdischarge region.

In a preferred embodiment for carrying out the process of our presentinvention, we utilize two concentric glass tubes provided with metalfoil: electrodes as illustrated in Figured. An outer cylindrical glasstube 28 is provided with a metallic plate or foil electrode 29 attachedto its outer surface. The inner concentric glass tube 30 is coated witha metallic sheet or foil electrode 30 upon its inner surface. Theannular-distance between concentric tubes 28 and 30 is optional anddetermines the volume capacity of the appait should be in a looselypowdered form. The value of the voltage from electric source 32 appliedbetween electrodes 29 and 3| is predetermined so as to produce a brushdischarge therebetween. One must be careful that the. voltage applied tothe apparatus produces the true brush discharge corresponding to curve20 of Figure 2. If the current is too low, the inefficient glowdischarge represented by curve 19 will take place; if the current is toohigh, a. spark discharge represented by curve 2| will take placeanddestroy any vitamins that might-be formed. In a par ticular example,glass cylinders 28 and 30 of one millimeter thickness and with anannular space of two millimeters required a voltage of the order of 8000volts to produce a brush discharge.

We have found that it is necessary to place the provitamin substance 35in the electrostatic field I within the actual brush discharge forantiarchit- I icl conversion. Experiments'have shown that iftheprovitamin substance 35 be placed at the outer regions of the annularspace, namely the regions 36 and 3'! immediately outside of the directelectrostatic field; negligible antirachitic vitamin conversion]results, demonstrating absence of ultra violet light conversion.

. An important feature of our present invention resides in the use .of acritical frequency for the most eflicient antirachitic conversion of theprovitamin substance; We" have -discovered that for most provitaminsubstances, particularly the sterols, the optimum frequency range ofconversion occurs between 250 and, 350 cycles. The efficiencyof"conversion" decreases with frequencies below 250 cycles, as well asfor frequencies above 350 cycles. Figure 5 is a qualitative curverepresentation' 38 of the relative conversion of provitamin substances"to antirachitic vitamins plotted withv respectfto the frequency of theapplied poteritialin cycles per second.

It is to be understood that a brush discharge occurs along the'points ofcurve 38 for the various frequencies plotted. At zero frequency arelatively've y small yield occurs As the frequency is increased to 250cycles, the yield correspondingly increases until the maximum. As thefrequency is further increased to about 350 cycles, the efficiency ofcon version continues near the maximum. For particular substances, apeaked nature of curve 38; will be evident" at a single criticalfrequency in the order of 250-350 cycles.

However, inFigure ,5,we have not" attempted to accurately represent anyparticular case but rather tov give an approximate conception of theeffect and range of thefrequency of the voltage ciency of conversiondiminishes until at 1000' cycles and above, the efficiency is relativelysmall.

As seen by curve 38 of Figure 5 "approximately 50% ofthe maximumefficiency or yield occurs with frequencies in the range'of 150 to 550cycles per second. By choosing the intermediate fre quency range of'250to 350 cycles per second the maximum efficiency or yield is approached.,For most provitamin substances a frequency of about 300 cyclespersecon'd'will produce best results.

It is necessary for a gaseous atmosphere to prevail between,thedischa'rge electrodes, therefore the solidprovitam'in 35 should bein a loosely powdered state. When air is used, ozoneis formed during theactivation process according to our invention. Ozone 'orjtheaction ofthe oxygen itself acts 'toslowly decompose the vitamins and accordinglysomewhat reduce the yield.

We have found that if the'activation process between the concentrictubes 28 and 30 is carried on in the presence of an inert gas such asnitro-,

gen thev efficiencyof conversion is materially increased. Nitrogen mayeither be' continuously .passed'through the substance "35 beingactivated in the annular chamber or may be confined to the annularchamber if it is made gas tight as will be understood by thoseskilled'in the art.

1N0 activation is'obse'r'ved if a solution of provitamin' fills theannular space, since a brush discharge cannot be established 'thru thesolvent.

A modification for activating the ergosterol 01' other provitaminresides incontinuously spraying it in the formof a fine d'us't betweenthe annular spaceofa relatively long structure. The

Till

ergosterol, crude cholesterol or other provitamin substance may bedissolved in a suitable solvent such as ether or alcoholand passedthrough the brush discharge in the annular space in the form of a finespray." Antirachitic conversion of provitamins to vitamins is evidentwith an exposure as low as two minutes. Increasing the time of exposureto a predetermined maximum of thetype and form of provitamin substancebeing.

activated.

Another important factor for increasing the efliciency of conversion'isthe temperature at which the conversion takes place. It is preferable tocarry out the process at a temperature of about C. although good resultswill be obtained at ordinary room temperatures. The temperature of thewhole apparatus, and therefore of the substance 35 being converted, maybe maintainedcool by means of a fan directly blowing thereon orpreferably by the continuous circulation of cooling water through thecentral circular tube 30 of the apparatus. Other suitable forms ofcooling will also be evident to thoseskilled in the art.

The true nature of the electro-chemical action during the brushdischarge has been in controversy for some time in the art. However, inthe present case, the activation appears to be due to the impingement ofions or activated atoms or moleculesproduced within the brush dischargefrom the gaseous dielectric, upon the provitamin substance which releasetheir energy to the provitamin, converting it to the antirachiticvitamin.

The important factors for the production of antirachitic vitamins fromprovitamins are the production of a brush discharge; placing aprovitamin substance such as ergosterol or crude cholesterol within thebrush discharge preferably insulated from the metallic electrodes byglass plates or the like; using a loosely powdered provitamin substancestructure, or in the form of fine dust spray, or a spray of a solutionof provitamin substance through the brush discharge; preferablymaintaining an inert gaseous atmosphere such as nitrogen and keeping thesubstance coolpreferably at 0 C. The production of'the brush dischargeshould be determined for each particular structure designed. Thenecessary voltage is determined'by the shape of the electrodes, theirsize and their spacing. Thefrequency of the applied voltage shouldpreferably be in a most efficient range for conversion. generally within250 and 350 cycles. A suitable source of the high voltage alternatingcurrent necessary for carrying out our process will be evident to thoseskilled in the art. An alternating current generator connected to astep-up transformer will provide the necessary high voltage. optimumfrequency. For small quantity production, an induction coil adjusted to,for example, 250 cycles of interruption, may be used to maintain thebrush discharge in an apparatus constructed to operate with thevoltages, for example 8000 volts, presented at the output thereof.

A convenient way of producing the desired frequency and voltages is togenerate the frequency by one of the usual types of variable audiooscillators, to amplify this by means of the standard types ofpie-amplifiers and amplifiers and to The alternator is adjusted to theproper feed this into a transformer designed to raise the voltage to thedesired range. A condenser board is used in connection with the finaltransformer so as to keep the current and voltage in phase.

The ergosterol or crude cholesterol is a concentrated antirachiticvitamin source, It is too potent for direct consumption. Small amountsare administered or eaten, preferably in combination with a. food ormedicine. A small percentage of the activated material is mixed with codliver oilyyeast, milk or other edible substance. No change in taste orodor of the food occurs. The antirachiticpotency of the edible materialtreated in this manner is equivalent to direct activation thereof. It ismuch more economical to produce edible or medicinal antirachitic substances by adding a small percentage of concen trated antirachiticvitamin content material to the substances, as compared to directactivation thereof. It is to be understood that antirachitically potentsubstances may be directly activated inaccordance with our presentinvention.

This application is a continuation in part of our application Serial No.723,314, filed May 1, 1934.

We claim:

1. The process for antirachitically activating provitamins whichcomprises introducing provitamin material into a gaseous region andapplying a voltage gradient across the gaseous region containing theprovitamin material for producing a gaseous brush discharge about theprovitamin material, whereby the provitamins are converted intoantirachitic vitamins by the brush discharge acting on the provitaminmaterial in the gaseous provitamins which comprises introducingprovitamin material in a powdered and loosely packed form into a gaseousregion and applying a voltage gradient across the gaseous regioncontaining the provitamin powder at substantially the maximum voltagewhich the region can support for producing a gaseous brush dischargeabout the provitamin material, whereby the provitamins are convertedinto antirachitic vitamins by the brush discharge acting on theprovitamin material in the gaseous atmosphere.

4. The process for antirachitically activating provitamins whichcomprises continuously passing a solution of provitamin material as afine spray through a gaseous region and applying a voltage gradientacross the gaseous region containing the provitamin spray atsubstantially the maximum voltage which the region can support forproducing a gaseous brush discharge about the provitamin material,whereby the provitamins are converted into antirachitic vitamins by thebrush discharge acting on the provitamin material.

5. The process for antirachitically activating provitamins whichcomprises introducing provitamin material into an inertgaseous'region'and applying a voltage gradient across the gaseous regioncontaining the provitamin material at substantially the maximum voltagewhich the region can support for producing a gaseous brush dischargeabout the provitamin material, whereby .the provitamins are convertedinto antirachitic vitamins by the brush discharge acting on theprovitamin material in the inert gaseous atmosphere.

6. The process for antirachitically activating provitamins whichcomprises introducing provitamin particles into a region of nitrogen gasand applying a voltage gradient across the gaseous region containing theprovitamin particles at substantially the maximum voltage which theregion can support for producing a gaseous brush discharge about theindividual provitamin particles, whereby the provitamins are con ertedinto antirachitic vitamins by the brush discharge acting on theprovitamin particles in the hi ogen atmos-\ phere.

'7. The process of antirachitically activating provitamins whichcomprises introduci g provitamin material into a gaseous region andapplyihg a voltage gradient across the gaseous region containing theprovitamin material for producing a gaseous brush discharge about theprovitamln converted into antirachitic vitamins by the interrupted brushdischarge acting on the provitamin material in the gaseous atmosphere.

8. The process of antirachitically activating provitamins whichcomprises introducing provitamin material into a gaseous region andapplying a voltage gradient across the gaseous region containing theprovitamin material at substantially the maximum voltage which theregion can support for producing a gaseous brush discharge about theprovitamin material, and generating the brush discharge with analternating voltage having a frequency of. about 300 cycles per second,whereby the provitamins are converted into antirachitic vitamins by thebrush discharge acting on the provitamin material in the gaseousatmosphere.

9. The process for antirachitically activating provitamins whichcomprises introducing provitamin particles into a gaseous region andapplying a voltage gradient across the gaseous region containing theprovitamin particles at substantially the maximum voltage which theregion can support for producing a gaseous brush discharge about theindividual provitamin particles, and generating the brush discharge withan alternating voltage having a frequency in the range of to 550 cyclesper second, whereby the provitamins are converted into antirachiticvitamins by the alternating brush discharge acting on the provltaminparticles in the gaseous atmosphere,

BENJAMIN KRAMER. SAMUEL NATELSON. ALBERT E. SOBEL.

